Scylla and Charybdis

In Greek mythology, Scylla and Charybdis were a pair of monsters who lived
on opposite ends of the Strait of Messina between Italy and Sicily Scylla
was originally a sea
nymph
who was loved by the sea god Poseidon*. Out of jealousy, Poseidon's wife
Amphitrite poisoned the waters in which Scylla bathed. This turned Scylla
into a six-headed beast with three rows of sharp teeth in each head. When
ships passed close by her, she struck out to grab and eat unwary sailors.

Charybdis was also a sea nymph, as well as the daughter of Poseidon. Zeus*
transformed her into a dangerous whirlpool across the strait from Scylla.
Ships sailing the strait were almost certain to be destroyed by one of the
monsters.

nymph
minor goddess of nature, usually represented as young and beautiful

epic
long poem about legendary or historical heroes, written in a grand
style

In the Greek
epic
the
Odyssey],
the hero Odysseus lost his ship in Charybdis, but he managed to save
himself by clinging to a tree overhanging the water. Later the whirlpool
spat up the ship, and Odysseus dropped to safety on its deck. The legend
of the two monsters gave birth to the phrase "between Scylla and
Charybdis," meaning a situation in which one has to choose between
two equally unattractive options.